CN2812465Y - Microphone package structure for micro-electromechanical system - Google Patents

Abstract

The utility model provides a microphone package structure for a micro-electromechanical system, which comprises an upper cover, a shell wall and a base board. The utility model also comprises an MEMS sound sensing element, an IC chip and other passive components, which are packaged and arranged on the base board. The upper cover is provided with a sound inlet stuck together with the base board and a shell wall to form a sound cavity. The frequency response performance of products after package is basically the same as the autogenous frequency response performance of the MEMS sound sensing element before the package by designing a proper sound cavity size. The MEMS sound sensing element is arranged on the base board in a proper way and reduces thermal stress generated by the difference of thermal expansion coefficients of the MEMS sound sensing element and the base board. The package structure can prevent the MEMS sound sensing element from being influenced by external environments and electromagnetic interference. The acoustic performance is difficult to be reduced by high temperature influences in using, packaging and SMT sticking processes.

Description

The mems microphone encapsulating structure

Technical field

The utility model relates to a kind of MEMS (micro electro mechanical system) sound transducer (being called for short mems microphone or MEMS microphone), relates in particular to a kind of mems microphone encapsulating structure.

Background technology

The silica-based sound transducer of MEMS (micro electro mechanical system) (Micro-electro-mechanical System) was disclosed in numerous patent documentations.For example, the 5th, 619,476,5,870,351,5,894,452 and 6,493, No. 288 U.S. Patent Publications the manufacture method of condenser type sonac.And the 5th, 146,435,5,452,268,6,535,460 and 6,870, No. 937 United States Patent (USP)s also disclose several MEMS (micro electro mechanical system) capacitance type sensors that are mainly used in audio section.Yet these patent documentation emphasis all concentrate on design and make on the silica-based diaphragm of mems microphone.In other words, mainly concentrate on the processing procedure aspect of mems microphone vibrating diaphragm chip.

For employed microphone in any electronic equipment, all need to select suitable packaged type, be subjected to the influence of external environment condition and electromagnetic interference to prevent the silica-based diaphragm of microphone.Say that again vibrating diaphragm chip also needs lead-in wire to be connected with external circuit, and will have suitable method that itself and external circuit are loaded on the substrate, these all need a kind of microphone package method that is suitable for producing in batches.

Compare with existing electret microphone, the mems microphone heat resistance is better, can bear Reflow Soldering temperature (promptly 260 ℃ and more than).Therefore, mems microphone can be designed to specific profile, is convenient to adopt surface-mounting equipment that it is mounted on the pcb board, thereby reduces assembly cost.

In some documents relevant for the disclosure of mems microphone packing forms.As the 6th, 7816, No. 231 United States Patent (USP)s, wherein a kind of mems microphone encapsulating structure of Miao Shuing partly is made up of mems microphone chip, substrate and loam cake etc.Substrate surface is used to support the mems microphone chip, and loam cake central authorities are conductive layers, and the edge part is limited.This marginal portion and the substrate composition shell that fuses, the middle body of loam cake separates certain distance to form the condenser type mems microphone with the surface of substrate.Also has a sound hole on the shell, so that voice signal incides on the vibrating diaphragm in the MEMS chip thus.Publication number is that 2005/0018864 United States Patent (USP) has disclosed a kind of silicone base capacitance microphone package, wherein also comprises silica-based mems microphone chip, substrate and loam cake.Be formed with a depression at its upper surface of base plate, microphone chip is attached to the upper surface of substrate and has covered the part of depression, thereby forms the back operatic tunes of microphone between microphone chip and substrate.Loam cake is positioned at the microphone chip top, and loam cake has a sound hole.

Above-mentioned encapsulation scheme has only provided a kind of protecting sheathing of silicon based microphone, and sound can be incided on wherein the silicon base vibrative membrane sheet.The influence that this layer shell also can protect the microphone silicon base vibrative membrane not destroyed by ambient light, electromagnetic interference and other possible physical property simultaneously.But above-mentioned encapsulation scheme does not solve the silicon based microphone encapsulation, uses and be assembled into some key issues in other complete machine process.These key issues mainly comprise following several aspect: microphone package size reasonable in design and operatic tunes size change the frequency response performance of transducer self with Min. ground; In the encapsulation process and the heat dissipation problem of the product after the encapsulation when the reflow ovens; Whether the microphone after the encapsulation can be used that SMT mounts and can encapsulation process be adapted to batch machining or the like.

The utility model content

Technical problem to be solved in the utility model is: a kind of mems microphone encapsulating structure is provided, it can not only make voice signal incide on wherein the sonic transducer silicon base vibrative membrane by sound hole, guarantee that simultaneously silicon base vibrative membrane is not subjected to the influence of ambient light and electromagnetic interference, and this encapsulating structure is suitable for SMT assembling, the more important thing is that its suitable operatic tunes design makes the frequency response performance of sensor unit self change minimum before and after encapsulation.

In order to solve the problems of the technologies described above, the utility model adopts following technical scheme: a kind of mems microphone encapsulating structure is provided, and it comprises: the loam cake 4 of a band sound hole 5; One shell wall 2, around and support loam cake 4; One substrate 1 is equipped with MEMS sound sensing element 6, IC chip 7 and other passive component 8 of mutual electrical connection on it, and substrate 1 supports shell wall 2 and loam cake 4; The operatic tunes 9 of described substrate 1, shell wall 2 and loam cake 4 bonding formation one maskable electromagnetic interference, described substrate 1 outer surface setting can surface-pasted pad 11.

Technique scheme is further improved and is: described loam cake 4 main bodys are cover plate 22, the upper surface of cover plate 22 is covered with thin metal layer 21 to form electromagnetic shielding, the edge of another side is provided with thin metal layer ring 24, described outer surface thin metal layer 21, cover plate 22 and thin metal layer ring 24 constitute sandwich structure, and thin metal layer 21 and thin metal layer ring 24 are electrically connected by the electrically conductive layer around the sound hole on the loam cake 45 23; Described shell wall 2 has sidewall 31, and metal protection layer 32 is coated on sidewall 31 inner surfaces; Edge thin layer 44 is set around described substrate 1 inner surface edge, and it is metal level or is coated with metal, is positioned at metallic plate 45 ground connection of MEMS sound sensing element 6 bottoms.

Technique scheme is further improved and is: the chip join part 54 that described MEMS sound sensing element 6 is used resilient material is installed on the substrate 1, and fill and sealing with elastic gum 55 in the gap between MEMS sound sensing element 6 peripheries and the substrate 1.

Technique scheme is further improved and is: metal protection layer 32 is provided with the sound absorbing layer of rough surface in the described shell wall 2.

The beneficial effects of the utility model are: because the operatic tunes 9 of substrate 1 of the present utility model, shell wall 2 and loam cake 4 bonding formation one maskable electromagnetic interference, described substrate 1 outer surface setting can surface-pasted pad 11, therefore it can prevent that MEMS sound sensing element is subjected to the influence of external environment and electromagnetic interference, and this encapsulating structure is suitable for SMT assembling, the more important thing is that its suitable operatic tunes design makes the frequency response performance of sensor unit self change minimum before and after encapsulation;

Secondly, because the chip join part 54 that MEMS sound sensing element 6 of the present utility model is used resilient material is installed on the substrate 1, fill and sealing with elastic gum 55 in gap between MEMS sound sensing element 6 peripheries and the substrate 1, when therefore installing by this way, can reduce greatly to guarantee that because of MEMS sound sensing element and substrate different thermal stress that produce of thermal coefficient of expansion between the two product is difficult for because of its acoustical behavior of temperatures involved in use, encapsulation and SMT assembling process;

Once more, because metal protection layer 32 is provided with the sound absorbing layer of rough surface in the shell wall 2 of the present utility model, therefore can improve absorbability, thereby improve damping coefficient, guarantee that further the Frequency Response of MEMS sound sensing element and open circuit sensitivity change minimum before and after encapsulation sound.

Below in conjunction with accompanying drawing the utility model is explained in detail, so that it is had clearer understanding.

Description of drawings

Fig. 1 is the schematic diagram of the utility model mems microphone encapsulating structure.

Fig. 2 is the low frequency equivalence acoustics line map of encapsulating structure shown in Figure 1.

Fig. 3 is the sensitivity comparison diagram that MEMS sound sensing element is installed in substrate (Figure 14 and Figure 15) front and back in the encapsulating structure by different way.

Fig. 4 be the utility model one specific embodiment can surface-pasted mems microphone encapsulating structure profile.

Fig. 5 be another specific embodiment of the utility model can surface-pasted mems microphone encapsulating structure profile.

Fig. 6 is the vertical view of loam cake in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Fig. 7 is the profile of loam cake in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Fig. 8 is the upward view of loam cake in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Fig. 9 is the vertical view of shell wall in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Figure 10 be in the specific embodiment encapsulating structure shown in Figure 9 shell wall along the profile of A-A ' line.

Figure 11 is the profile of another kind of form shell wall in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Figure 12 is the upward view of substrate in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Figure 13 is the vertical view (MEMS sound sensing element, IC and relevant passive device have been installed) of substrate in the encapsulating structure of specific embodiment shown in the Figure 4 and 5.

Figure 14 is the profile of MEMS sound sensing element when being installed on the substrate.

Figure 15 is the profile when being installed in MEMS sound sensing element on the substrate with other method.

Figure 16 is the jigsaw floor map of mems microphone encapsulating structure when producing in batches of the utility model specific embodiment.

Figure 17 is that mems microphone encapsulating structure jigsaw shown in Figure 16 is split into the enlarged drawing of overlooking before the single product.

Embodiment

We can both comprise the consideration of acoustic connection, also comprise from the angle consideration that is suitable for producing in batches from different aspect design mems microphone encapsulating structures.The operatic tunes that mems microphone encapsulation back forms will be tried one's best to sensor chip frequency response Effect on Performance and be eased down to minimum value.Mems microphone can also be used to that SMT mounts and can stand the impact test of higher temperature during through Reflow Soldering at encapsulation process and final products.

With reference to the schematic diagram of mems microphone encapsulating structure shown in Figure 1, it be the encapsulating structure of rectangle, and the length of encapsulating structure is that L, width are W, highly are H.The loam cake of this encapsulating structure has a sound hole.The radius of sound hole is that a, the degree of depth are h.MEMS sound sensing element is installed in the encapsulating structure.The normal frequency of the interior air of the operatic tunes can be expressed from the next in the encapsulating structure:

$f=\frac{\mathrm{\ω}}{2\mathrm{\π}}=\frac{c}{2}\sqrt{{\left(\frac{l}{L}\right)}^2+{\left(\frac{m}{W}\right)}^2+{\left(\frac{n}{H}\right)}^2}---\left(1\right)$

Wherein f represents n normal frequency, and unit is a hertz.L, m, n can be unequal integer, and they are desirable from 0 value to infinite.Every group of different resonance mode of integer representative.L, W, H represent the encapsulating structure size, and unit is a rice.C is the velocity of sound, and unit is a meter per second.

When the sound source in the small size encapsulating structure is excited, it may motivate one or more standing waves, i.e. the normal mode of air vibration in the encapsulating structure.Suppose that the intensity of sound source is constant and have single-frequency, this frequency will be identical with the normal frequency of air vibration in the encapsulating structure so.The acoustic pressure Pn of normal attitude will increase until its root mean square size (when microphone forward and is backward moved a wavelength in time with the space on average) equal

$P_n=\frac{K}{K_n}---\left(2\right)$

Wherein K representative is mainly by the intensity of sound source and position and the sound source constant determined by the operatic tunes volume of encapsulation, and the Kn representative mainly absorbs the amount of the sound intensity by encapsulating structure and by the determined damping constant of operatic tunes volume of encapsulation.The sound-absorbing material that adopts in the package casing is many more, and the Kn value is big more, thereby its average pressure value is more little.

When the half-wavelength of sound wave much larger than L, and sound hole radius a is during much smaller than loam cake length and width size (L, W), the low frequency equivalence acoustics line map of mems microphone encapsulating structure shown in Figure 1 as shown in Figure 2.Wherein, P1 represents the acoustic pressure at sound hole place in the encapsulating structure, the final acoustic pressure that arrives MEMS sound sensing element of P2 representative, and M represents the acoustic mass at encapsulating structure sound hole place, C1 represents the acoustic capacitance of air in the encapsulating structure, and C2 represents the acoustic compliance of MEMS sound sensing element vibrating diaphragm.

Under low frequency, the acoustic pressure that arrives MEMS sound sensing element can be expressed as:

${\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">P</figure-callout>}}_2=\frac{{\left[\mathrm{j\&omega;}({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2)\right]}^{-1}}{{\left[\mathrm{j\&omega;}({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2)\right]}^{-1}+\mathrm{j\&omega;M}}{P}_1---\left(3\right)$

The existence of sound hole will make Helmholtz resonator of the whole formation of encapsulating structure in the loam cake shown in Figure 1, and its resonance frequency is:

$f_0=\frac{1}{2\mathrm{\&pi;}}\sqrt{\frac{1}{M({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2)}}---\left(4\right)$

Wherein the existence of C2 has reduced the resonance frequency of encapsulating structure shown in Figure 1.By equation (4) as can be known: encapsulating structure need be designed so that the acoustic compliance C2 of the acoustic capacitance C1 of air in its chamber much larger than MEMS sound sensing element vibrating diaphragm.In this case, the resonance frequency of encapsulation and the combination of MEMS sound sensing element will equate with the resonance frequency of encapsulation self.

Again because

$M=\frac{\mathrm{\&rho;}{V}_1}{{\mathrm{<figure-callout\; id="2"\; label="S"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">S</figure-callout>}}^2}=\frac{\mathrm{\&rho;h}}{S}---\left(5\right)$

${\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">C</figure-callout>}}_1=\frac{{\mathrm{<figure-callout\; id="2"\; label="V"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">V</figure-callout>}}_2}{\mathrm{\&rho;}{C}^2}---\left(6\right)$

Wherein ρ represents the mass density of air, and V1 represents the volume of loam cake sound hole, and S represents the cross-sectional area of sound hole, and V2 represents the volume of encapsulating structure inner chamber, and C represents the velocity of sound.

By equation (5) and (6), equation (4) can further be expressed as:

$f_0=\frac{1}{2\mathrm{\&pi;}}\frac{\mathrm{<figure-callout\; id="1"\; label="SC\; V"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">SC</figure-callout>}}{\sqrt{V_{}}}=\frac{\mathrm{<figure-callout\; id="2"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">C</figure-callout>}}{2\mathrm{\&pi;}}\frac{\sqrt{S}}{\sqrt{h\&CenterDot;V_2}}---\left(7\right)$

From equation (7), as seen,, need to increase the cross-sectional area of sound hole, perhaps reduce upper cover thickness, perhaps reduce the effective volume of encapsulation inner chamber for the frequency range of the mems microphone that improves encapsulating structure shown in Figure 1.

We discuss the sensitivity of the mems microphone after the encapsulation now.For the condenser microphone that does not encapsulate, its open circuit sensitivity η o is:

${\mathrm{\&eta;}}_0=\frac{{\mathrm{<figure-callout\; id="2"\; label="EC"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">EC</figure-callout>}}_2}{\mathrm{xA}}---\left(8\right)$

Wherein the E representative is added in the bias voltage on the microphone, and x represents the distance between vibrating diaphragm and the back pole plate, and A represents the effective area of vibrating diaphragm.

Sensitivity after the encapsulation is:

$\mathrm{\&eta;}=\frac{{\mathrm{<figure-callout\; id="2"\; label="EC"\; filenames="Y20052005984500141.png,Y20052005984500171.png"\; state="\{\{state\}\}">EC</figure-callout>}}_2}{\mathrm{xA}}\&CenterDot;\frac{1}{1-{\mathrm{\&omega;}}^{2}M({\mathrm{<figure-callout\; id="1"\; label="C"\; filenames="Y20052005984500141.png,Y20052005984500191.png"\; state="\{\{state\}\}">C</figure-callout>}}_1+C_2)}={\mathrm{\&eta;}}_0\frac{1}{1-{\left(\frac{f}{f_0}\right)}^2}---\left(9\right)$

Wherein η o is provided by equation (8), and fo can be according to calculating in the equation (7).Obviously as seen: along with the increase of mems microphone frequency range after the encapsulation, it is more little that change is compared in its sensitivity and encapsulation not from equation (9).And the mems microphone external dimensions after the encapsulation is when being subjected to spatial arrangement on terminal use's the pcb board and limiting, most preferred embodiment of the present utility model provides a kind of technical scheme that reduces to encapsulate effective volume, thereby improve the mems microphone frequency range after the encapsulation, and then make Frequency Response and open circuit sensitivity after the mems microphone encapsulation change minimum.

As shown in Figure 4, the mems microphone encapsulating structure of the utility model most preferred embodiment comprises: loam cake 4, around and support shell wall 2, the substrate 1 of loam cake 4 and be installed on the substrate 1 and packed MEMS sound sensing element 6, IC chip 7 and other passive component 8.Have sound hole 5 on the loam cake 4, and be bonded together with substrate 1, shell wall 2 and form the operatic tunes 9, basic identical by MEMS sound sensing element frequency response performance before designing suitable operatic tunes size and making product frequency response performance and encapsulation after the encapsulation.Between substrate 1 and shell wall 2 and shell wall 2 and loam cake 4, adopt glue 3 bonding.Select the height of suitable shell wall 2 to make between the upper surface of MEMS sound sensing element 6 and the loam cake 4 and have enough gaps 10.Bottom design at substrate 1 has pad 11, so that the mems microphone after the encapsulation can adopt SMT to be mounted on the pcb board.Substrate 1 is made by the FR-4 material, to mate with terminal use's pcb board temperature characterisitic.Sound hole 5 on the loam cake 4 can be chosen in the position away from MEMS sound sensing element 6, drops on the surface of MEMS sound sensing element 6 easily to prevent dust, can prevent that also the moisture that produces when the people speaks is splashed on its surface.

If MEMS sound sensing element 6 has firm surface and can not be subjected to moisture and effect of dust, sound hole 5 also can select to be positioned at the position directly over the MEMS sound sensing element 6 as shown in Figure 5.

Figure 6 shows that the vertical view of loam cake 4.The main body of the loam cake 4 of band sound hole 5 is a cover plate 22, it is made by the FR-4 material, the upper surface of cover plate 22 is covered with thin metal layer 21 to form electromagnetic shielding, the edge of another side is provided with thin metal layer ring 24, (as shown in Figure 7), thin metal layer 21, cover plate 22 and thin metal layer ring 24 form sandwich structure.Thin metal layer 21 links to each other by the electrically conductive layer 23 around the sound hole 5 with thin metal layer ring 24.Figure 8 shows that the upward view of loam cake 4.When adopting conducting resinl to bond to loam cake 4 on the shell wall 2, loam cake 4, shell wall 2 and substrate 1 have formed the sealing operatic tunes, are not subjected to the influence of electromagnetic interference with the components and parts in the protection operatic tunes.

Figure 9 shows that the vertical view of shell wall 2.Shell wall 2 has the sidewall of being made by the FR-4 material 31.Metal protection layer 32 is coated on sidewall 31 inner surfaces with shield electromagnetic interference.Internal layer 34 is the sound absorbing layers that are coated on the metal protection layer 32, with the acoustic resonance that may form in the decay operatic tunes 9.Bevel angle 33 provides stronger mechanical support for shell wall 2.Owing to its symmetrical configuration, also can reduce the acoustic resonance of formation possible in the operatic tunes 9.Another advantage of bevel angle structure is to have reduced effective encapsulation volume.According to the argumentation of front, it can change to Min. the Frequency Response and the open circuit sensitivity of MEMS sound sensing element 6.Figure 10 shows that shell wall 2 among Fig. 9 along A-A ' line profile.Internal layer 34 has coarse surface, can improve the absorbability to sound, thereby improves damping coefficient.When the physical dimension of the operatic tunes 9 is enough little, to such an extent as to compare with the upper limit of mems microphone operating frequency, the longest edge lengths of the operatic tunes 9 also can save internal layer 34, as shown in figure 11 during less than the half-wavelength of sound in the air.

Figure 12 shows that the upward view of substrate 1.The body supports plate 41 of substrate 1 is made by the FR-4 material, and four angles of supporting bracket are provided with pad 11, and one of them pad 41 has the bevel angle that is used for easy identification.Figure 13 shows that the vertical view (and having installed sensing element, IC and relevant passive device) of substrate 1.Edge thin layer 44 is for metal level or be coated with metal, being electrically connected with shell wall 2, and then the enclosed cavity of formation shield electromagnetic interference.Metallic plate 45 ground connection that are positioned at MEMS sound sensing element 6 bottoms are with further shield electromagnetic interference.Leg 48 on the binding lead-in wire 46 electrical connection MEMS sound sensing elements 6 and the leg on the substrate 1.IC chip 7 is mounted on the leg 52 on the substrate 1, perhaps can be bundled in the below of substrate 1.Connecting line 51 on the substrate 1 makes between all relevant electronic components such as the passive device 8 and is electrically connected.And MEMS sound sensing element 6 can at first adopt chip join part 54 to attach it on the substrate 1, and gap between it and the substrate 1 is filled and sealed to other elastic gum 55 along MEMS sound sensing element 6 periphery.

Detailed maps when Figure 14 and Figure 15 are installed on the substrate 1 for MEMS sound sensing element 6.As mentioned above, substrate 1 is mainly made by the FR-4 material, has good thermal coefficient of expansion.And MEMS sound sensing element 6 is made by the monocrystalline silicon with relatively low thermel expansion coefficient.In the SMT assembling process that encapsulation process and terminal manufacturer are carried out, the MEMS microphone will bear the Reflow Soldering temperature up to 260 degrees centigrade.In so high temperature environment, thermal coefficient of expansion between substrate 1 and the MEMS sound sensing element 6 differs too big, if use hard chip join part directly MEMS sound sensing element 6 to be installed on the substrate 1, will make MEMS sound sensing element 6 bear bigger thermal stress and distortion, cause sensitivity decline even complete failure.According to specific embodiment of the utility model, see shown in Figure 14, at first can adopt chip join part 54 to be bonded on the substrate 1 at angle of MEMS sound sensing element 6, this will reduce the thermal stress that the difference because of thermal coefficient of expansion between MEMS sound sensing element 6 and the substrate 1 produces greatly.Then, adopt a kind of very soft elastic gum 55, such as RTV glue, along MEMS sound sensing element 6 around seal its with substrate 1 between formation the gap.

As shown in figure 15, elastic gum 55 fills up the space between MEMS sound sensing element 6 and the shell wall 2.This mode will reduce the effective volume of the operatic tunes 9, and then improve the upper limit of mems microphone operating frequency.Thus, with the open circuit sensitivity after 6 encapsulation of Min. ground change MEMS sound sensing element, referring to Fig. 4.

Fig. 3 is the sensitivity comparison diagram that MEMS sound sensing element is installed in substrate (Figure 14 and Figure 15) front and back in the encapsulating structure by different way.

According to most preferred embodiment of the present utility model, the encapsulation process of mems microphone comprises assembling substrates 1, shell wall 2 and loam cake 4.On the substrate 1 at first welding go up IC chip 7 and passive component 8, re-use elastic gum 55 MEMS sound sensing element 6 be bonded on the substrate 1, the line lead of going forward side by side binding makes it be electrically connected with interlock circuit in the substrate 1.Use elastic gum 55 seal clearances then.The substrate of assembling completion is aimed at shell wall 2 and loam cake 4 and is bonding, has just obtained packaged mems microphone.In order to improve efficiency of assembling, substrate 1 can adopt the jigsaw form, and jigsaw quantity can be according to mounting and the production capacity of cutting tool and selecting voluntarily.Components and parts on the substrate adopt automatic chip mounting or binding, and the shell wall and the loam cake that mount the substrate jigsaw of completion and identical jigsaw structure are bonding, have formed jigsaw assembly 60 as shown in figure 16.

Jigsaw assembly 60 shown in Figure 16 will cut into single mems microphone, has the line of cut 61 of being convenient to the cutting blade walking on the panel assembly 60, and through hole 62 is used for panel assembly 60 is installed in Cutting platform.Location notch 63 is positioned at panel assembly 60 peripheries, and its position need be along the major axis symmetry of panel assembly 60, so that the direction of clear identification panel assembly 60.Figure 17 shows that the enlarged drawing of overlooking of mems microphone jigsaw assembly 60.When cutting blade during along line of cut 61 cut surface board components 60, packaged single mems microphone 64 just can have been separated at an easy rate.

Claims (9)

1. mems microphone encapsulating structure, it comprises:

The loam cake (4) of one band sound hole (5);

One shell wall (2), around and support loam cake (4);

One substrate (1) is equipped with MEMS sound sensing element (6), IC chip (7) and other passive component (8) of mutual electrical connection on it, and substrate (1) supports shell wall (2) and loam cake (4);

It is characterized in that: the operatic tunes (9) of described substrate (1), shell wall (2) and the bonding formation one maskable electromagnetic interference of loam cake (4), described substrate (1) outer surface setting can surface-pasted pad (11).

2. mems microphone encapsulating structure as claimed in claim 1 is characterized in that:

Described loam cake (4) main body is cover plate (22), the upper surface of cover plate (22) is covered with thin metal layer (21) to form electromagnetic shielding, the edge of another side is provided with thin metal layer ring (24), described outer surface thin metal layer (21), cover plate (22) and thin metal layer ring (24) constitute sandwich structure, and thin metal layer (21) and thin metal layer ring (24) are electrically connected by the electrically conductive layer (23) all around of the sound hole (5) on the loam cake (4);

Described shell wall (2) has sidewall (31), and metal protection layer (32) is coated on sidewall (31) inner surface;

Edge thin layer (44) is set around described substrate (1) inner surface edge, and it is metal level or is coated with metal, is positioned at metallic plate (45) ground connection of MEMS sound sensing element (6) bottom.

3. mems microphone encapsulating structure as claimed in claim 2, it is characterized in that: the chip join part (54) that described MEMS sound sensing element (6) is used resilient material is installed on the substrate (1), and fill and sealing with elastic gum (55) in the gap between MEMS sound sensing element (6) periphery and the substrate (1).

4. as claim 1,2 or 3 described mems microphone encapsulating structures, it is characterized in that: the material of main part of described cover plate (22), sidewall (31) and substrate (1) is FR-4.

5. as claim 2 or 3 described mems microphone encapsulating structures, it is characterized in that: the interior metal protection layer of described shell wall (2) (32) is provided with the sound absorbing layer of rough surface.

6. mems microphone encapsulating structure as claimed in claim 4 is characterized in that: the interior metal protection layer of described shell wall (2) (32) is provided with the sound absorbing layer of rough surface.

7. mems microphone encapsulating structure as claimed in claim 1 is characterized in that: the sound hole (5) on the described loam cake (4) is positioned at away from the position of MEMS sound sensing element (6) or is positioned at position directly over the MEMS sound sensing element (6).

8. mems microphone encapsulating structure as claimed in claim 1 is characterized in that: described shell wall (2) is provided with the bevel angle (33) of symmetrical configuration.

9. mems microphone encapsulating structure as claimed in claim 1 is characterized in that: four angles of the body supports plate (41) of described substrate (1) are provided with pad (11), and one of them pad (41) has the bevel angle that is used for easy identification.

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